I've put this computer together and every thing's working fine but I had to buy a new hard drive. I installed the hard drive and its a Seagate Barracuda 7200.10 250 Gb's. It's SATA so I found a 4-Molex to SATA converter so it gets power, and It's connected to SATA 1 connection on the motherboard. It's an asus a7nbx motherboard with a 2.6 Ghz amd chip and a radeon 9700 pro 128 mb. Now the computer boots but it will not recognize the new hard drive. The hard drive's got power though and its running fine. Even when i try to install windows, windows says it cannot detect a hard drive.

What's wrong?

as i was typing this, i thought i might have to clear cmos data. Is that it?

go to south bridge configurations to enable sata. I recently got a new sata harddrive for my old system with a A7V880 motherboard, which is kinda similar to yours. Are you overclocking? If my motherboard goes over 2.0ghz then my sata ports don't function. so i can only overclock 1.8ghz to 2.0ghz

I know where the south bridge is but, I don't know where or how to enable SATA. Is it a jumper? Non of them are labeled and I don't have the Layout diagram of the board because I got from someone else.

Check in the bios. On a lot of the new motherboards you have to actually tell it how to treat SATA. There should be an option somewhere in the bios to make it treat the sata as either raid or ide. You want it to be set to IDE mode.